1. Field of the Invention
The present invention relates to high-frequency switch modules that switch between transmission and reception of communication signals having certain frequencies and, more particularly, to a high-frequency switch module including a field effect transistor (FET) switch.
2. Description of the Related Art
Various wireless communication methods are currently adopted in communication apparatuses including mobile phones. For example, multiband Global System for Mobile Communication (GSM) methods have been adopted in Europe. Multiple communication signals (transmission and reception signals) using different frequency bands exist in the GSM methods and the frequency bands including an 850 MHz band, a 900 MHz band, a 1,800 MHz band, and a 1,900 MHz band exist in the GSM methods. In addition, Universal Mobile Telecommunication System (UMTS) methods using a 2,100 MHz band exist as next-generation wireless communication methods. There are cases in which high-frequency switch modules are used in front-ends units of communication apparatuses that transmit and receive the communication signals within the multiple frequency bands with one antenna (for example, refer to Japanese Unexamined Patent Application Publication No. 2005-197855). The high-frequency switch modules switch signal transmission paths from antennas to transmission or reception circuits of the communication signals within desired frequency bands by using FET switches.
Japanese Unexamined Patent Application Publication No. 2005-197855 discloses a high-frequency switch module provided with a Single Pole n Throw (SPnT) switch element using a GaAs FET switch. The SPnT switch element includes one antenna port and n-number switch ports. A transmission or reception circuit provided for each frequency band is connected to each switch port. The transmission and reception circuits of a total number n or more are provided.
Since the wireless communication methods of different numbers or types are used in different nations, the number and types of circuits to be connected to switch elements are varied depending on the specifications of the communication apparatuses. Accordingly, in the related art, it is necessary to separately design the configuration of the switch element and the configuration of the mounting board of the switch element in accordance with the number and/or types of the wireless communication methods, thus increasing the design time and the manufacturing cost due to the separate design. Consequently, it is desirable to reduce the design time and the manufacturing cost.
In addition, in general, it is necessary to increase isolation of the communication signals between the transmission or reception circuit connected to the switch element and the antenna in the front-end unit in each communication apparatus. However, since the signals are apt to wrap around through an FET switch in the high-frequency switch module using the FET switch, it is necessary to take measures against the wrapping around of the signals.